U.S. patent application number 09/901274 was filed with the patent office on 2002-01-24 for optical arrangement for deflecting a light beam, particularly in two substantially mutually perpendicular directions and confocal scanning microscope.
This patent application is currently assigned to Leica Microsystems Heidelberg GmbH. Invention is credited to Engelhardt, Johann.
Application Number | 20020008904 09/901274 |
Document ID | / |
Family ID | 7648467 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020008904 |
Kind Code |
A1 |
Engelhardt, Johann |
January 24, 2002 |
Optical arrangement for deflecting a light beam, particularly in
two substantially mutually perpendicular directions and confocal
scanning microscope
Abstract
The present invention relates to an optical arrangement for
deflecting a light beam (1, 14), in particular in two substantially
mutually perpendicular directions (2, 3), preferably for applying
to confocal scanning microscopes, having two mirrors (8, 10) which
can be rotated by means of a rotary drive (4, 5) in each case about
mutually perpendicular axes--the x-axis (6) and y-axis (7)--one of
the two mirrors (8, 10) being assigned a further mirror (9) in a
prescribed angular position in a rotationally fixed fashion such
that the mutually assigned mirrors (8, 9)--first and second
mirrors--rotate jointly about the y-axis (7), and in so doing
rotate the light beam (1, 14) about a pivot (11) which lies on the
axis of rotation (6)--the x-axis--of the third mirror (10). In
order to minimize and, in the ideal case, to eliminate the
distortion errors produced by the arrangement, the optical
arrangement is characterized in that the mirrors (8, 9, 10) are
arranged in such a way that the optical axis of the light beam (12)
running between the second and the third mirrors (9, 10) always
lies substantially in a plane containing the x-axis (6) and
perpendicular to the y-axis (7).
Inventors: |
Engelhardt, Johann; (Bad
Schoenborn, DE) |
Correspondence
Address: |
Simpson, Simpson & Snyder, L.L.P.
5555 Main Street
Williamsville
NY
14221
US
|
Assignee: |
Leica Microsystems Heidelberg
GmbH
Am Friedensplatz 3 D-68165
Mannheim
DE
|
Family ID: |
7648467 |
Appl. No.: |
09/901274 |
Filed: |
July 9, 2001 |
Current U.S.
Class: |
359/368 ;
359/201.1; 359/385 |
Current CPC
Class: |
G02B 21/0048
20130101 |
Class at
Publication: |
359/368 ;
359/201; 359/385 |
International
Class: |
G02B 026/08; G02B
021/00; G02B 021/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2000 |
DE |
100 33 549.7 |
Claims
What is claimed is:
1. An optical arrangement for deflecting a light beam in two
substantially mutually perpendicular directions comprising a first
rotary drive defining a first axis of rotation, a second rotary
drive defining a second axis of rotation, wherein the axes are
mutually perpendicular, a first mirror rotated by the first rotary
device, a second mirror rotated by the second rotary device, a
third mirror arranged in an angular position with respect to the
first mirror wherein the first and third mirror rotate jointly
about the first axis, a pivot point is defined on the second
mirror, wherein the light beam pivots about the pivot which lies on
the second of rotation of the second mirror, and the first, second
and third mirrors are arranged, that a light beam running between
the second and the third mirrors and the second axis of rotation
are always substantially in one plane and the plane is
perpendicular to the first axis of rotation.
2. Arrangement according to claim 1, wherein the light beam running
from the second mirror to the third mirror always impinges
substantially at the point on a surface of the second mirror and
the pivot point lies on a intersection of the first and second axes
of rotation.
3. Arrangement according to claim 1, wherein the first axis of
rotation of the first and third mirror is substantially collinear
with the light beam incident on the first mirror.
4. Arrangement according to claim 1, wherein a fourth mirror is
arranged between the first rotary drive rotating and the first
mirror.
5. Arrangement according to claim 4, characterized in that the
fourth mirror is arranged fixed and a housing is provided for
mounting the first and third mirror.
6. Arrangement according to claim 5, wherein the housing has at
least two openings formed therein through which light beam enters
and emerges.
7. Arrangement according to claim 5, characterized in that the
housing is directly connected to the first axis of the first rotary
drive.
8. Arrangement according to claim 1, wherein the second mirror is
directly connected to the second rotary drive.
9. Arrangement according to claim 1, wherein the first and second
rotary drives are mounted on a holding device and the holding
device is arranged to rotate about the first axis of rotation.
10. Arrangement according to claim 5, wherein a rotary bearing is
provided in the housing, which accommodates the first and third
mirror and the rotary bearing is mounted in the holding device.
11. Arrangement according to claim 10, wherein the axis of the
rotary bearing of the housing is arranged collinearly with the axis
of the rotary bearing of the holding device.
12. Arrangement according to claim 5, wherein the housing
accommodating the first and third mirror and the first rotary drive
rotating the housing are combined to form a replaceable module and
wherein the second mirror and the second rotary drive are combined
to form a replaceable module.
13. Arrangement according to claim 1, wherein a galvanometer or a
stepping motor serves as the first and second rotary drive.
14. A confocal scanning microscope comprises: an optical
arrangement for deflecting a light beam in two substantially
mutually perpendicular directions, the optical arrangement has a
first rotary drive defining a first axis of rotation, a second
rotary drive defining a second axis of rotation, wherein the axes
are mutually perpendicular, a first mirror rotated by the first
rotary device, a second mirror rotated by the second rotary device,
a third mirror arranged in an angular position with respect to the
first mirror wherein the first and third mirror rotate jointly
about the first axis, a pivot point is defined on the second
mirror, wherein the light beam pivots about the pivot which lies on
the second axis of rotation of the second mirror, and the first
second and third mirrors are arranged, that a light beam running
between the second and the third mirrors and the second axis of
rotation are always substantially in one plane and the plane is
perpendicular to the first axis or rotation.
15. The confocal scanning microscope as defined in claim 14,
wherein the first axis of rotation of the first and third mirror is
substantially collinear with the light beam incident on the first
mirror.
16. The confocal scanning microscope as defined in claim 14,
wherein a fourth mirror is arranged between the first rotary drive
rotating and the first mirror.
17. The confocal scanning microscope as defined in claim 16,
wherein a housing is provided for mounting the first, third and
fourth mirror.
18. The confocal scanning microscope as defined in claim 17,
wherein the housing has at least two openings formed therein
through which light beam enters and emerges.
19. The confocal scanning microscope as defined in claim 17,
wherein the housing is directly connected to the first axis of the
first rotary drive.
20. The confocal scanning microscope as defined in claim 14,
wherein the second mirror is directly connected to the second
rotary drive.
21. The confocal scanning microscope as defined in claim 14,
wherein the first and second rotary drives are mounted on a holding
device and the holding device is arranged to rotate about the first
axis of rotation.
22. The confocal scanning microscope as defined in claim 17,
wherein a rotary bearing is provided in the housing, which
accommodates the first and third mirror and the rotary bearing is
mounted in the holding device.
23. The confocal scanning microscope as defined in claim 22,
wherein the axis of the rotary bearing of the housing is arranged
collinearly with the axis of the rotary bearing of the holding
device.
24. The confocal scanning microscope as defined in claim 17,
wherein the housing accommodating the first and third mirror and
the first rotary drive rotating the housing are combined to form a
replaceable module and wherein the second mirror and the second
rotary drive are combined to form a replaceable module.
25. The confocal scanning microscope as defined in claim 17,
wherein the replaceable modules have means for exact positioning,
which are configured as guide elements and/or stop elements.
26. The confocal scanning microscope as defined in claim 14,
wherein at least one of the mirrors is replaced by an optically
active component, which consists essentially of an AOD
(Acousto-Optical Deflector), an EOD (Electro-Optical Deflector) or
aDMD (Digital Micro-Mirror Device).
27. The confocal scanning microscope as defined in claim 14,
wherein at least one optically active component is upstream and/or
downstream of the first, second and third mirror, and the optically
active component consists essentially of an AOD (Acousto-Optical
Deflector), an EOD (Electro-Optical Deflector) or aDMD (Digital
Micro-Mirror Device).
28. A confocal scanning microscope comprises: an optical
arrangement for deflecting a light beam in two substantially
mutually perpendicular directions, wherein the optical arrangement
has a housing which accommodates a first, third and fourth mirror
and a holding device which accommodates a second mirror and the
holding device rotatable mounts the housing wherein the holding
device and the housing are configured as replaceable modules.
29. The confocal scanning microscope as defined in claim 28,
wherein the optical arrangement for deflecting a light beam in two
substantially mutually perpendicular directions has a first rotary
drive, mounted to the housing, defining a first axis of rotation, a
second rotary drive, mounted to the holding device, defining a
second axis of rotation, wherein the axes are mutually
perpendicular, a first mirror is rotated by the first rotary
device, a second mirror is rotated by the second rotary device, a
third mirror arranged in the housing in an angular position with
respect to the first mirror, a pivot point is defined on the second
mirror, wherein the light beam pivots about the pivot which lies on
the second axis of rotation of the second mirror, and the first
second and third mirrors are arranged that a light beam running
between the second and the third mirrors and the second axis of
rotation are always substantially in one plane and the plane is
perpendicular to the first axis of rotation.
30. The confocal scanning microscope as defined in claim 29,
wherein the housing has at least two openings formed therein
through which light beam enters and emerges.
31. The confocal scanning microscope as defined in claim 29,
wherein a rotary bearing is provided in the housing, and the rotary
bearing is mounted in the holding device.
32. The confocal scanning microscope as defined in claim 31,
wherein the axis of the rotary bearing of the housing is arranged
collinearly with the axis of the rotary bearing of the holding
device.
33. The confocal scanning microscope as defined in claim 28,
wherein the replaceable modules have means for exact positioning,
which are configured as guide elements and/or stop elements.
34. A confocal scanning microscope comprises: an optical
arrangement for deflecting a light beam in two substantially
mutually perpendicular directions, the optical arrangement has a
first rotary drive defining a first axis of rotation, a second
rotary drive defining a second axis of rotation, wherein the axes
are mutually perpendicular, a first mirror rotated by the first
rotary device, a second mirror rotated by the second rotary device,
a third mirror arranged in an angular position with respect to the
first mirror wherein the first and third mirror rotate jointly
about the first axis, a pivot point is defined on the second
mirror, wherein the light beam pivots about the pivot point which
lies on the second axis of rotation of the second mirror, and
wherein the light beam running from the second mirror to the third
mirror always impinges substantially at the point on a surface of
the second mirror and the pivot point lies on a intersection of the
first and second axes of rotation.
35. The confocal scanning microscope as defined in claim 34,
wherein the first axis of rotation of the first and third mirror is
substantially collinear with the light beam incident on the first
mirror.
36. The confocal scanning microscope as defined in claim 34,
wherein a fourth mirror is arranged between the first rotary drive
rotating and the first mirror.
37. The confocal scanning microscope as defined in claim 36,
wherein a housing is provided for mounting the first, third and
fourth mirror.
38. The confocal scanning microscope as defined in claim 34,
wherein the first and second rotary drives are mounted on a holding
device and the holding device is arranged to rotate about the first
axis of rotation.
39. The confocal scanning microscope as defined in claim 38,
wherein the housing accommodating the first and third mirror and
the first rotary drive rotating the housing are combined to form a
replaceable module and wherein the second mirror and the second
rotary drive are combined to form a replaceable module.
40. The confocal scanning microscope as defined in claim 39,
wherein the replaceable modules have means for exact positioning,
which are configured as guide elements and/or stop elements.
41. The confocal scanning microscope as defined in claim 34 wherein
the first and second rotary drive are configured as a
galvanometer.
42. The confocal scanning microscope as defined in claim 34 wherein
the first and second rotary drive are configured as a stepping
motor.
43. The confocal scanning microscope as defined in claim 34,
wherein at least one of the mirrors is replaced by an optically
active component, which consists essentially of an AOD
(Acousto-Optical Deflector), an EOD (Electro-Optical Deflector) or
aDMD (Digital Micro-Mirror Device).
44. The confocal scanning microscope as defined in claim 34,
wherein at least one optically active component is upstream and/or
downstream of the first, second and third mirror, and the optically
active component consists essentially of an AOD (Acousto-Optical
Deflector), an EOD (Electro-Optical Deflector) or aDMD (Digital
Micro-Mirror Device).
45. A confocal scanning microscope comprises: an optical
arrangement for deflecting a light beam in two substantially
mutually perpendicular directions, wherein the optical arrangement
has a housing which accommodates a first, third and fourth mirror
and a holding device which accommodates a second mirror and the
holding device rotatable mounts the housing, and wherein the
holding device and the housing are configured as replaceable
modules, a first rotary drive, mounted to the housing, defining a
first axis of rotation, a second rotary drive, mounted to the
holding device, defining a second axis of rotation, wherein the
axes are mutually perpendicular and the first mirror is rotated by
the first rotary device, and the second mirror is rotated by the
second rotary device, a third mirror being arranged in the housing
in an angular position with respect to the first mirror, a pivot
point is defined on the second mirror, wherein the light beam
pivots about the pivot point which lies on the second axis of
rotation of the second mirror, and the first, second and third
mirrors are arranged that a light beam running between the second
and the third mirrors and the second axis of rotation are always
substantially in one plane and the plane is perpendicular to the
first axis of rotation.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This invention claims priority of the German patent
application DE 100 33 549.7 filed Jul. 11, 2000 which is
incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to an optical arrangement for
deflecting a light beam in particular in two substantially mutually
perpendicular directions, preferably for applying to confocal
scanning microscopes.
BACKGROUND OF THE INVENTION
[0003] An optical arrangement of the generically determinative type
is disclosed in DE 196 54 210 C2. The arrangement known from this
printed publication for scanning a beam advantageously permits high
scanning rates during deflection of the light beam.
[0004] Disadvantageous in the known arrangement are scanning errors
which arise in the form of a hyperbolic distortion, particularly
after the scanning of an object with a confocal scanning
microscope. The distortion can certainly be corrected
computationally, but is problematical under some circumstances
since the image cannot be uniquely reconstructed computationally,
particularly in the case of object scanning in which the scanning
theorem is not fulfilled.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is therefore to specify
and develop a generically determinative arrangement for deflecting
a light beam in two substantially mutually perpendicular directions
in such a way that the distortion errors generated by the
arrangement can be minimized and, in the ideal case,
eliminated.
[0006] The above object is accomplished by the arrangement
according to the invention which comprises: a first rotary drive
defining a first axis of rotation, a second rotary drive defining a
second axis of rotation, wherein the axes are mutually
perpendicular, a first mirror rotated by the first rotary device, a
second mirror rotated by the second rotary device, a third mirror
arranged in an angular position with respect to the first mirror
wherein the first and third mirror rotate jointly about the first
axis, a pivot point is defined on the second mirror, wherein the
light beam pivots about the pivot which lies on the second of
rotation of the second mirror, and the first, second and third
mirrors are arranged, that a light beam running between the second
and the third mirrors and the second axis of rotation are always
substantially in one plane and the plane is perpendicular to the
first axis of rotation.
[0007] It is a further object of the present invention to specify a
confocal scanning microscope which has an optical arrangement for
deflecting a light beam in two substantially mutually perpendicular
directions and eliminates distortion errors generated by the
optical arrangement.
[0008] The above object is accomplished by a confocal scanning
microscope comprising: an optical arrangement for deflecting a
light beam in two substantially mutually perpendicular directions,
the optical arrangement has a first rotary drive defining a first
axis of rotation, a second rotary drive defining a second axis of
rotation, wherein the axes are mutually perpendicular, a first
mirror rotated by the first rotary device, a second mirror rotated
by the second rotary device, a third mirror arranged in an angular
position with respect to the first mirror wherein the first and
third mirror rotate jointly about the first axis, a pivot point is
defined on the second mirror, wherein the light beam pivots about
the pivot which lies on the second axis of rotation of the second
mirror, and the first second and third mirrors are arranged, that a
light beam running between the second and the third mirrors and the
second axis of rotation are always substantially in one plane and
the plane is perpendicular to the first axis or rotation.
[0009] An additional object of the invention is to provide a
confocal scanning microscope which has a simple designed optical
arrangement for deflecting a light beam in two substantially
mutually perpendicular directions and thereby eliminating
distortion errors generated by the optical arrangement.
[0010] The above object is accomplished by a confocal scanning
microscope comprising: an optical arrangement for deflecting a
light beam in two substantially mutually perpendicular directions,
wherein the optical arrangement has a housing which accommodates a
first, third and fourth mirror and a holding device which
accommodates a second mirror and the holding device rotatable
mounts the housing wherein the holding device and the housing are
configured as replaceable modules.
[0011] According to the invention, it has been initially realized
that the hyperbolic distortion named in DE 196 54 210 C2 can be
minimized or eliminated whenever the rotation of the mutually
assigned mirrors--first and third mirrors--, which rotate jointly
about the first axis of rotation, deflect the light beam after
reflection at the third mirror only along one direction or one
straight line. Likewise, during rotation of the second mirror about
the second axis of rotation the light beam need be deflected only
along one direction or one straight line. Consequently, the
decoupling of the rotation of the mirrors about their respective
axes of rotation relative to the direction of deflection
corresponding to the directions of deflection of the respective
other axis of rotation is a fundamental precondition for deflecting
the light beam with little distortion. The arrangement according to
the invention of the first and third mirrors relative to the second
mirror permits such a decoupling, since the optical axis of the
light beam reflected by the third mirror and running to the second
mirror always impinges on the second mirror, and the point of
impingement of the optical axis of the light beam lies on the
second axis of rotation of the second mirror and always lies in the
plane perpendicular to the first axis of rotation in the way
according to the invention during rotation of the two mirrors
assigned to one another.
[0012] In a further advantageous way, the mirrors are arranged in
such a way that the optical axis of the light beam running from the
third mirror to the second mirror always impinges substantially at
a point on the mirror surface of the second mirror which is the
point of intersection of the two axes of rotation. Owing to this
arrangement of the mirrors, when the first and third mirrors are
rotated independently of the pivot angle thereof, the optical axis
of the light beam reflected by the second mirror is always pivoted
about the same point, and this advantageously maintains a
telecentric beam path even downstream of the mirror arrangement.
Since the point of impingement of the light beam reflected by the
third mirror on the second mirror is always substantially the same
independently of the angular position of the second mirror, with
reference to the direction of deflection of the third mirror, as
well, the light beam reflected or deflected by the third mirror is
always pivoted about the point which lies on the mirror surface of
the second mirror and is the point of intersection of the two axes
of rotation. Consequently, the light beam deflected by the mirrors
is deflected, in particular, in two substantially mutually
perpendicular directions.
[0013] It is of no consequence for the mode of operation of the
arrangement for deflecting a light beam whether the light beam to
be deflected is a non-expanded or an expanded, or collimated, light
beam.
[0014] In a concrete embodiment, the optical axis of the light beam
incident on the first mirror, and the optical axis of the light
beam reflected by the second mirror are substantially collinear.
This holds, however, only when the second mirror is located in the
non-deflected position, that is to say the second rotary drive
rotating the second mirror is located in its rest position. The
collinear arrangement of the optical axes is advantageous, in
particular, for the adjustment and/or mounting of the arrangement
since, without the three mirrors of the deflecting arrangement, the
incident light beam points at the same point which results when the
three mirrors of the deflecting arrangement are introduced into the
optical beam path. In a further embodiment, the axis of rotation of
the first and third mirrors is substantially collinear with the
optical axis of the light beam incident on the first mirror. The
result is that, when the first and third mirrors rotate about the
first axis or rotation, the point of impingement of the optical
axis of the incident beam on the first mirror is always the same
independently of the angular position of the first and third
mirrors. However, the precondition for this is that the first
mirror is arranged in such a way that the axis of rotation of the
first and third mirrors and the mirror surface of the first mirror
have a point of intersection.
[0015] In a further embodiment, the axis of rotation of the first
and third mirrors is substantially collinear with the optical axis
of the light beam reflected by the second mirror. This holds,
likewise, only when the second mirror is not in the deflected
position.
[0016] In a concrete embodiment, it is provided that the first
rotary drive rotating the first and third mirrors about first axis
of rotation is arranged spatially between the first and the second
mirrors. As a result, it may also advantageously be possible for
collinearity to exist between the optical axis of the light beam
incident on the first mirror and the optical axis of the light beam
reflected by the second mirror. The optical arrangement for
deflecting the light beam could, without further deflection,
deflect or pivot a light beam running in one direction, the pivot
of the deflected light beam lying on the optical axis of the
originally running light beam. The deflection which can thus be
achieved would continue to have a central axis coinciding with the
direction of the originally running light beam, as it were a
"straight-ahead" deflection or lateral spreading.
[0017] In an alternative embodiment, a fourth mirror is arranged
between the first rotary drive rotating the first and third mirrors
about the first axis of rotation and the first mirror. This mirror
permits a deflection of the light beam by a virtually arbitrary
angle such that the light beam deflected or spread laterally by the
optical arrangement has a central axis which does not coincide with
the original direction of propagation of the light beam upstream of
the reflection at the fourth mirror.
[0018] The fourth mirror is arranged fixed in this case. If
appropriate, it can be moved for the purpose of adjustment and/or
during production, but it is locked in its position after the
adjustment.
[0019] The first and third mirrors are arranged in a housing. The
housing has at least two openings through which the light beams can
enter and emerge. The housing has corresponding holding means on
which it is possible for the two mirrors to be glued or fastened in
another way. The housing is preferably made from light material
and, after being produced by shaping--for example by chip-forming
shaping--ideally has an adequate precision such that, after
introduction of the two mirrors, there is no need for any further
adjustment of the mirrors relative to the housing. Production which
is reproducible and quick is advantageously rendered possible
thereby. The light incident on the first mirror enters the housing
through one opening. The light reflected by the third mirror
emerges from the housing through the other opening. No further
openings are provided in the housing, in order to avoid pollution
by dust particles. The housing could, however, have a removable
side wall which can be opened for cleaning purposes even after a
lengthy operating period.
[0020] The housing is directly connected to the first rotary drive,
preferably directly to the first axis of rotation of the latter. An
indirect connection of the housing to the rotary drive would be
conceivable as an alternative to this, for example via a gear,
cardan joint or an uncoiling leaf element. A transmission ratio
could thereby reduce or increase the possible angle of rotation of
the rotary drive if the mirrors need to be rotated over a smaller
or larger angular range. Again, the maximum or minimum rate of
rotation or pivoting could be raised or lowered thereby. An
uncoiling leaf element--such as is normally used with magnetic
heads of computer hard disks--could rotate the housing about an
axis which need not be collinear with the axis of rotation of the
rotary drive.
[0021] In the same way, the second mirror could be connected either
directly or indirectly to a second rotary drive. In the former
case, the second mirror is preferably connected directly to the
second axis of rotation of the second rotary drive in the latter
case, the second mirror could be connected to the second rotary
drive via a gear, cardan joint or an uncoiling leaf element.
[0022] The two rotary drives can be fitted either indirectly or
directly on a holding device. The holding device could, for
example, be a plate on which the two rotary drives are fastened. It
is thereby ensured that the two rotary drives are arranged in a
well-defined position relative to one another. Moreover, the
holding device could be designed as an angled plate, a
double-angled plate or a housing with appropriate holes.
[0023] The holding device is advantageously arranged rotatably. In
a preferred embodiment, the holding device rotates about the first
axis of rotation. Owing to the rotation of the holding device, the
two rotary drives of the three mirrors are rotated jointly about
the axis of the holding device such that the orientation of the
beam deflecting directions is variable. This is advantageous, in
particular, because the orientation of the direction of deflection
of the second mirror rotating on its own. The second mirror
rotating on its own is generally operated at a considerably higher
scanning rate than the housing accommodating the first and third
mirrors, which has a very much greater mass. Consequently, the fast
direction of beam deflection of the second mirror rotating on its
own can be orientated at will by rotating the holding device, and
this is of great advantage, in particular, for applications in
confocal scanning microscopy.
[0024] The housing accommodating the two first mirrors has a rotary
bearing. This rotary bearing could be mounted in the holding
device. If no common holding device is provided for the two rotary
drives, the rotary bearing could be mounted directly in the housing
accommodating the arrangement for deflecting a light beam. In a
concrete embodiment, the axis of the rotary bearing is collinear
with the axis of rotation of the first and third mirrors.
[0025] It is provided, furthermore, that the holding device has at
least one rotary bearing which permits the holding device to be
rotated about an axis. The rotary bearing of the housing of the
first and third mirrors could now be mounted in a rotary bearing of
the holding device. In this case, the axis of the rotary bearing of
the housing of the first and third mirrors could be arranged
collinearly with the axis of the rotary bearing of the holding
device.
[0026] With regard to a flexible use of the optical arrangement
according to the invention for deflecting a light beam, it is
provided that the individual components are of modular design and
are easy to replace. For this purpose, it would be possible, for
example, to combine the housing accommodating the first and third
mirrors and the rotary drive rotating in the housing to form a
replaceable module. Furthermore, the second mirror and the rotary
drive rotating it could be combined to form a replaceable module.
One option thereby would be to replace the housing with the first
and third mirrors together with the rotary drive thereof in order,
for example, to vary the angular range of the deflection about the
first axis of rotation. The second mirror and the rotary drive
rotating it could also be replaced as a module in order, for
example, to insert a rotary drive of higher or lower scanning rate
into the optical arrangement. A flexible expansion of the field of
application of the arrangement according to the invention is
advantageously possible thereby. Furthermore, the overall holding
device could be designed in the form of a replaceable module such
that the complete arrangement according to the invention for
deflecting a light beam is replaceable.
[0027] In order to avoid complicated and/or lengthy adjustments, it
is provided that the replaceable modules and/or the holding device
of modular design have means for exact positioning. These means
could be designed, for example, in the form of guide elements
and/or stop elements.
[0028] A galvanometer could be used as rotary drive for the housing
accommodating the first and third mirrors, or for the second
mirror. A resonant galvanometer could also be used to achieve a
high scanning and/or deflecting rate. A resonant galvanometer is
preferably used as rotary drive for the second mirror rotating on
its own. It would also be possible to use a stepping motor as
rotary drive.
[0029] One of the mirrors could be replaced by an active optical
component for the purpose likewise of achieving a high scanning or
deflecting rate. Use could be made for this purpose of, for
example, an AOD (Acousto-Optical Deflector), EOD (Electro-Optical
Deflector) or a DMD (Digital Micro-Mirror Device). It would be
conceivable in this case to replace the second mirror rotating on
its own by an active optical component. This optical component
could be fitted in the holding device.
[0030] Furthermore, at least one optically active component could
be arranged upstream and/or downstream of the optical arrangement
for deflecting a light beam, that is to say the three mirrors. The
optically active component in this case could be an AOD, EOD or
DMD, as well.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] There are various possibilities for configuring and
developing the teaching of the present invention in an advantageous
way. In conjunction with the explanation of the preferred exemplary
embodiments of the invention with the aid of the drawing generally
preferred configurations and developments of the teaching are also
explained. In the drawing:
[0032] FIG. 1 shows a diagrammatic illustration of a first
exemplary embodiment of an optical arrangement according to the
invention for deflecting a light beam,
[0033] FIG. 2 shows a diagrammatic illustration of a second
exemplary embodiment according to the invention, and
[0034] FIG. 3 shows a diagrammatic illustration of a third
exemplary embodiment according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] FIG. 1 shows an optical arrangement for deflecting a light
beam 1 in two substantially mutually perpendicular directions 2, 3.
The optical arrangement has a first and second mirror 8 and 10
which can be respectively rotated by a first and second rotary
drive 4 and 5 about mutually perpendicular axes--the fist-axis of
rotation 7 and the second axis of rotation 6--the first mirror 8
being assigned a third mirror 9 in a prescribed angular position in
a rotationally fixed fashion such that the first and third mirror 8
and 9, that is to say first and third mirror 8 and 9, assigned to
one another, rotate jointly about the fist-axis of rotation 7, and,
in this case, rotate the light beam 1 about a pivot point 11 which
lies on the second axis of rotation 6 of the second mirror 10.
[0036] According to the invention, the first, third and second
mirror 8, 9 and 10 are arranged in such a way that the optical axis
of the light beam 12 running between the third and the second
mirrors 9 and 10 always lies substantially in a plane containing
the second axis of rotation and being perpendicular to the first
axis or rotation 7.
[0037] The first, third and second mirrors 8, 9 and 10 are arranged
in such a way that the optical axis of the light beam 12 running
from the third mirror 9 to the second mirror 10 always impinges
substantially at a point 11 on the mirror surface of the second
mirror 10 which is the point of intersection of the two axes of
rotation 6, 7. Consequently, the deflected light beam 13 always
pivots or rotates about the pivot 11.
[0038] The optical axis of the light beam 14 incident on the first
mirror 8, and the optical axis of the light beam 13 reflected by
the second mirror 10 are substantially collinear when the second
mirror 10 is in the non-deflected position which is illustrated in
FIGS. 1 to 3. The first axis of rotation 7 of is substantially
collinear with the optical axis of the light beam 14 incident on
the first mirror 8. Furthermore, the first axis of rotation 7 of
the first and third mirror 8 and 9 is substantially collinear with
the optical axis of the light beam 13 reflected by the second
mirror 10 when the second mirror 10 is located in the non-deflected
position.
[0039] A fourth mirror 15 is arranged fixed between the rotary
drive 5, which rotates the first and third mirrors 8 and 9 about
the first axis of rotation 7. The first and third mirrors 8 and 9
are arranged in a housing 16. The housing 16 has two openings 17,
18. The light beam 14 incident on the first mirror 8 can pass
through the opening 17, and the light beam 12 reflected by the
third mirror 9 can run through the opening 18 to the second mirror
10.
[0040] The housing 16 is connected directly to the rotary drive 5,
specifically directly to the mechanical axis of rotation thereof.
The second mirror 10 is connected directly to the second rotary
drive 4, to the mechanical axis of rotation thereof.
[0041] The first and second rotary drives 5 and 4 are fitted
directly on the holding device 19 shown in FIG. 3. The holding
device 19 is arranged rotatably and rotates about the first axis of
rotation 7. Owing to the rotation of the holding device 19 about
the first axis of rotation 7, it is possible to vary the
orientation of the beam-deflecting devices 2, 3, and thus of the
deflection pattern 20. The fast beam deflection, realized in this
exemplary embodiment, along the direction 2 by the solely rotating
second mirror 10 can therefore be advantageously orientated
arbitrarily.
[0042] The axis of rotation 7 of the first and third mirrors 8 and
9 is substantially collinear with the optical axis of the light
beam 14 incident on the first mirror 8. Furthermore, the first axis
of rotation 7 of the first and third mirrors 8 and 9 is
substantially collinear with the optical axis of the light beam 13
reflected by the second mirror 10 when the second mirror 10 is
located in the non-deflected position.
[0043] A fourth mirror 15 is arranged fixed between the first
rotary drive 5, which rotates the first and third mirrors 8 and 9
about the first axis of rotation 7. The first and third mirrors 8
and 9 are arranged in a housing 16. The housing 16 has two openings
17, 18. The light beam 14 incident on the first mirror 8 can pass
through the opening 17, and the light beam 12 reflected by the
third mirror 9 can run through the opening 18 to the second mirror
10.
[0044] FIG. 2 shows an exemplary embodiment according to the
invention in which the housing 16 accommodating the first and third
mirrors 8 and 9 has a rotary bearing 21. The rotary bearing 21 has
a passage 22 through which the deflected light beam 13 can pass. It
can be seen from FIG. 2 that the rotary bearing 21 is mounted in
the holding device 19. Consequently, the housing 16 is mounted,
firstly, by the first rotary drive 5 and, secondly, by the rotary
bearing 21 during the rotary movement about the first axis of
rotation 7. The rotary bearing 21 of the housing 16 of the first
and third mirrors 8 and 9 is mounted in a rotary bearing 23 of the
holding device 19. The rotary bearing 23 is connected to a housing
(not illustrated) which accommodates the arrangement according to
the invention for deflecting a light beam.
[0045] It is to be seen in outline from FIG. 3 that the axis of the
rotary bearing 21 of the housing 16 of the first and third mirrors
8 and 9 is arranged collinearly with the axis of the rotary bearing
23 of the holding device 19. These two axes coincide with the first
axis of rotation 7.
[0046] The components of the optical arrangement for deflecting a
light beam are designed in the form of modular components which are
easy to replace. In this case, the housing 16 accommodating the
first and third mirrors 8 and 9 and the first rotary drive 5
rotating the housing 16, as shown in FIGS. 1 and 2, form a
replaceable module. The second mirror 10 and the second rotary
drive 4 rotating it form a further replaceable module. The overall
holding device 19 shown in FIG. 3 is likewise of modular design.
The first rotary drive 5 rotating the housing 16 is designed as a
galvanometer which can execute oscillations in a frequency range
from 10 to 800 Hz. The second rotary drive 4 rotating the second
mirror 10 is designed as a resonant galvanometer and oscillates at
a frequency of 4 kHz. The holding device 19 is rotated about the
first axis of rotation 7 by a stepping motor (not illustrated).
[0047] Finally, it may be pointed out quite specifically that the
exemplary embodiments discussed above serve only to describe the
claimed teaching, but do not limit the latter to the exemplary
embodiments.
* * * * *